With the advancement of science and technology, fluid transportation devices used in many sectors such as pharmaceutical industries, computer techniques, printing industries or energy industries are developed toward elaboration and miniaturization. The fluid transportation devices are important components that are used in for example micro pumps, micro atomizers, printheads or industrial printers. Therefore, it is important to provide an improved structure of the fluid transportation device.
For example, in the pharmaceutical industries, pneumatic devices or pneumatic machines use motors or pressure valves to transfer gases. However, due to the volume limitations of the motors and the pressure valves, the pneumatic devices or the pneumatic machines are bulky in volume. In other words, the conventional pneumatic device fails to meet the miniaturization requirement, and is not suit to be installed in or cooperated with a portable equipment. Moreover, during operations of the motor or the pressure valve, annoying noise is readily generated.
FIG. 8 is a schematic cross-sectional view illustrating a conventional miniature pneumatic device. As shown in FIG. 8, the miniature pneumatic device 2 comprises a miniature fluid control device 2A and a miniature valve device 2B. In this embodiment, the miniature fluid control device 2A comprises a housing 2a, a piezoelectric actuator 23, a first insulation plate 241, a conducting plate 25 and a second insulation plate 242. The housing 2a comprises a gas collecting plate 26 and a base 20. The base 20 comprises a gas inlet plate 21 and a resonance plate 22. The piezoelectric actuator 23 is aligned with the resonance plate 22. The gas inlet plate 21, the resonance plate 22, the piezoelectric actuator 23, the first insulation plate 241, the conducting plate 25, the second insulation plate 242 and the gas collecting plate 26 are stacked on each other sequentially. The miniature valve device 2B comprises a valve film 27 and a gas outlet plate 28. The valve film 27 and the gas outlet plate 28 of the miniature valve device 2B are stacked on each other and positioned on the gas collecting plate 26 of the miniature fluid control device 2A. Moreover, a sealing adhesive 29 is coated on the periphery region of the valve film 27 to prevent from leakage. Consequently, a simple slim-type miniature pneumatic device 2 is assembled.
The miniature pneumatic device is applicable to equipment or machine and has small, miniature, silent, portable and comfortable benefits. However, since the sealing adhesive 29 is coated on the periphery region of the valve film 27 to prevent from leakage and the valve film 27 is adhered between the gas outlet plate 28 and the gas collecting plate 26, some drawbacks occur. For example, the long-term vibration may destroy the airtight condition of the sealing adhesive. Because of the insufficient airtight condition, the working characteristics and flowrate of the miniature pneumatic device 2 is adversely affected. Moreover, since the space between the gas outlet plate 28 and the gas collecting plate 26 is very small, it is difficult to coat the sealing adhesive 29.
Therefore, there is a need of providing a miniature pneumatic device in order to eliminate the above drawbacks.